ZnO nanoarchitecture-based nano-and microdevices came into the focus due to their multifunctional operation. In this work, we summarize cost-effective procedures to grow ZnO nano-and microstructures, namely hydrothermal growth and electrochemical deposition. These techniques allow the controllable growth of ZnO nano-and microarchitectures at relatively low temperatures, below 100 °C, and do not require sophisticated equipment. We report on technological details for synthesis of ZnO and its characterization and applications in different novel devices such as gas sensors. Nanosensors and microsensors were fabricated using a focused ion beam and by metal welding an individual nano-and microstructure to form rigid contacts. Devices made from pure and doped ZnO nanostructures are presented and discussed. Developed nano-and microdevice structures show promising performances and are quite attractive for further investigations in sensor applications. Several factors determine the gas sensing mechanism of pure and doped ZnO micro-and nanowire/nanorods and discussions on this are summarized.